RESUMO
Ever since the discovery of restriction fragment length polymorphism (RFLP) by Kan and Dozy (1978), several significant achievements have been made in DNA polymorphism studies over the past two decades. It is indeed the observation of hypervariable minisatellites as dispersed throughout the genome by Jeffreys et al. (1985a) has added new dimension and that gave the impetus to the prolific application of DNA polymorphism in many fields such as medicine, agriculture, population genetics, and forensic science. Here we enumerate the historical background, basis, analytical approaches and applications associated with DNA polymorphism studies. We also present a detailed account of various DNA probes in vogue such as cloned (single and multilocus) minisatellites/VNTRs, synthetic oligonucleotides and the advantages and limitations of each probe/system. The recent advances made in PCR based DNA typing is also highlighted.